<?php

/*

	EmailAddressValidator Class
	http://code.google.com/p/php-email-address-validation/

	Released under New BSD license
	http://www.opensource.org/licenses/bsd-license.php

	Sample Code
	----------------
	$validator = new EmailAddressValidator;
	if ($validator->check_email_address('test@example.org')) {
		// Email address is technically valid
	}

*/

class EmailAddressValidator {

	/**
	 * Check email address validity
	 * @param   strEmailAddress     Email address to be checked
	 * @return  True if email is valid, false if not
	 */
	public function check_email_address($strEmailAddress) {

		// If magic quotes is "on", email addresses with quote marks will
		// fail validation because of added escape characters. Uncommenting
		// the next three lines will allow for this issue.
		//if (get_magic_quotes_gpc()) {
		//    $strEmailAddress = stripslashes($strEmailAddress);
		//}

		// Control characters are not allowed
		if (preg_match('/[\x00-\x1F\x7F-\xFF]/', $strEmailAddress)) {
			return false;
		}

		// Check email length - min 3 (a@a), max 256
		if (!$this->check_text_length($strEmailAddress, 3, 256)) {
			return false;
		}

		// Split it into sections using last instance of "@"
		$intAtSymbol = strrpos($strEmailAddress, '@');
		if ($intAtSymbol === false) {
			// No "@" symbol in email.
			return false;
		}
		$arrEmailAddress[0] = substr($strEmailAddress, 0, $intAtSymbol);
		$arrEmailAddress[1] = substr($strEmailAddress, $intAtSymbol + 1);

		// Count the "@" symbols. Only one is allowed, except where
		// contained in quote marks in the local part. Quickest way to
		// check this is to remove anything in quotes. We also remove
		// characters escaped with backslash, and the backslash
		// character.
		$arrTempAddress[0] = preg_replace('/\./'
										 ,''
										 ,$arrEmailAddress[0]);
		$arrTempAddress[0] = preg_replace('/"[^"]+"/'
										 ,''
										 ,$arrTempAddress[0]);
		$arrTempAddress[1] = $arrEmailAddress[1];
		$strTempAddress = $arrTempAddress[0] . $arrTempAddress[1];
		// Then check - should be no "@" symbols.
		if (strrpos($strTempAddress, '@') !== false) {
			// "@" symbol found
			return false;
		}

		// Check local portion
		if (!$this->check_local_portion($arrEmailAddress[0])) {
			return false;
		}

		// Check domain portion
		if (!$this->check_domain_portion($arrEmailAddress[1])) {
			return false;
		}

		// If we're still here, all checks above passed. Email is valid.
		return true;

	}

	/**
	 * Checks email section before "@" symbol for validity
	 * @param   strLocalPortion     Text to be checked
	 * @return  True if local portion is valid, false if not
	 */
	protected function check_local_portion($strLocalPortion) {
		// Local portion can only be from 1 to 64 characters, inclusive.
		// Please note that servers are encouraged to accept longer local
		// parts than 64 characters.
		if (!$this->check_text_length($strLocalPortion, 1, 64)) {
			return false;
		}
		// Local portion must be:
		// 1) a dot-atom (strings separated by periods)
		// 2) a quoted string
		// 3) an obsolete format string (combination of the above)
		$arrLocalPortion = explode('.', $strLocalPortion);
		for ($i = 0, $max = sizeof($arrLocalPortion); $i < $max; $i++) {
			 if (!preg_match('.^('
							.    '([A-Za-z0-9!#$%&\'*+/=?^_`{|}~-]'
							.    '[A-Za-z0-9!#$%&\'*+/=?^_`{|}~-]{0,63})'
							.'|'
							.    '("[^\\\"]{0,62}")'
							.')$.'
							,$arrLocalPortion[$i])) {
				return false;
			}
		}
		return true;
	}

	/**
	 * Checks email section after "@" symbol for validity
	 * @param   strDomainPortion     Text to be checked
	 * @return  True if domain portion is valid, false if not
	 */
	protected function check_domain_portion($strDomainPortion) {
		// Total domain can only be from 1 to 255 characters, inclusive
		if (!$this->check_text_length($strDomainPortion, 1, 255)) {
			return false;
		}
		// Check if domain is IP, possibly enclosed in square brackets.
		if (preg_match('/^(25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9]?[0-9])'
		   .'(\.(25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9]?[0-9])){3}$/'
		   ,$strDomainPortion) ||
			preg_match('/^\[(25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9]?[0-9])'
		   .'(\.(25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9]?[0-9])){3}\]$/'
		   ,$strDomainPortion)) {
			return true;
		} else {
			$arrDomainPortion = explode('.', $strDomainPortion);
			if (sizeof($arrDomainPortion) < 2) {
				return false; // Not enough parts to domain
			}
			for ($i = 0, $max = sizeof($arrDomainPortion); $i < $max; $i++) {
				// Each portion must be between 1 and 63 characters, inclusive
				if (!$this->check_text_length($arrDomainPortion[$i], 1, 63)) {
					return false;
				}
				if (!preg_match('/^(([A-Za-z0-9][A-Za-z0-9-]{0,61}[A-Za-z0-9])|'
				   .'([A-Za-z0-9]+))$/', $arrDomainPortion[$i])) {
					return false;
				}
				if ($i == $max - 1) { // TLD cannot be only numbers
					if (strlen(preg_replace('/[0-9]/', '', $arrDomainPortion[$i])) <= 0) {
						return false;
					}
				}
			}
		}
		return true;
	}

	/**
	 * Check given text length is between defined bounds
	 * @param   strText     Text to be checked
	 * @param   intMinimum  Minimum acceptable length
	 * @param   intMaximum  Maximum acceptable length
	 * @return  True if string is within bounds (inclusive), false if not
	 */
	protected function check_text_length($strText, $intMinimum, $intMaximum) {
		// Minimum and maximum are both inclusive
		$intTextLength = strlen($strText);
		if (($intTextLength < $intMinimum) || ($intTextLength > $intMaximum)) {
			return false;
		} else {
			return true;
		}
	}

}

?>